Conciseness

The body is three sentences — 'Use this skill to choose Python verification.' and 'Read `references/nox-make.md` before running broad Python checks or adding test coverage.' — with zero padding and no explanation of concepts Claude already knows. Every token earns its place, matching anchor 5.

Actionability

'Read `references/nox-make.md` before running broad Python checks or adding test coverage' is a concrete, executable directive with specific conditions, and the referenced file supplies complete commands (make targets, nox sessions). It is not 5 because the body itself includes no inline quick-start command for the common case (e.g., `make tst`), and not 3 because the pointer is specific and condition-gated rather than vague.

Workflow Clarity

This is a simple skill with a single unambiguous action — read the reference before running broad checks or adding coverage — so per the simple-skill exception, workflow clarity scores 5. The skill's purpose is itself verification, so no validation checkpoints are missing.

Progressive Disclosure

The body is a clear overview with one well-signaled, one-level-deep reference (`references/nox-make.md`, verified to exist), and the reference contains the detailed commands without further nesting. Content is appropriately split between overview and detail, matching anchor 5.

Specificity

The description lists multiple specific concrete actions — 'Select and run Python SDK verification with nox, Makefile targets, Ruff, mypy, pytest markers, sanity tests, type inference checks, and build checks' — giving comprehensive coverage of the verification surface. It exceeds anchor 4 ('minor gaps in coverage') because the action list enumerates the full verification toolset rather than leaving gaps.

Completeness

It explicitly answers both: what ('Select and run Python SDK verification with nox, Makefile targets, Ruff, mypy, pytest markers, sanity tests, type inference checks, and build checks') and when ('Use when adding Python tests, diagnosing Python CI, or validating Python SDK/provider changes'), matching the anchor-5 example pattern exactly. It is not 4 because the 'when' clause is explicit and concrete rather than merely improvable.

Trigger Term Quality

Triggers like 'adding Python tests', 'diagnosing Python CI', and 'validating Python SDK/provider changes' are phrases users would naturally say, alongside tool names (nox, Ruff, mypy, pytest). It falls short of anchor 5's comprehensive synonym/extension coverage — e.g., no 'unit tests', 'run the tests', or '.py' style variations — but is clearly above anchor 3's partial coverage.

Distinctiveness Conflict Risk

It carves a clear niche (Python SDK verification) with distinct triggers and an explicit negative boundary — 'Do not use for TypeScript-only checks' — which actively prevents wrong-skill triggering. Conflict risk is minimal, matching anchor 5.